UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


RESULTS  OF  RICE  EXPERIMENTS 
AT  CORTENA,   1923 

AND 

PROGRESS  IN  EXPERIMENTS  IN  WATER 

GRASS  CONTROL  AT  THE  BIGGS 

RICE  FIELD  STATION  1922-23 


BY 
CARROLL  F.  DUNSHEE  and  JENKIN  W.  JONES 


BULLETIN  No.  375 

February,   1924 


UNIVERSITY  OF  CALIFORNIA  PRINTING  OFFICE 

BERKELEY,  CALIFORNIA 

1924 


Results  of  Rice  Experiments  at  Cortena,  1923 

AND 

PROGRESS  IN  EXPERIMENTS  IN  WATER  GRASS  CONTROL 
AT  THE  BIGGS  RICE  FIELD  STATION,  1922-23 

By  CARROLL  F.  DUNSHEE  and  JENKIN  W.  JONES 


CONTENTS 

PAGE 

Introduction 5 

I.    Results  of  rice  experiments  at  Cortena  in  1923 7 

Preparation  of  field  and  seeding 8 

Effect  of  method  of  seeding  and  submergence  on  water  grass  control 8 

Effect  of  date  of  seeding  and  submergence  on  water  grass  control  and  yields 

of  rice 11 

Miscellaneous  experiments 12 

Water  requirements  of  rice  plants 13 

Experiments  with  field  crops 15 

Studies  of  the  physical  conditions  of  rice  soils 15 

Chemical  studies  on  waters  and  soils 16 

Changes  in  bacterial  flora  of  rice  soils 21 

II.    Progress  in  experiments  on  water  grass  control  at  the  Biggs  Rice  Field 

Station,  1922-23 23 

Scope  and  method  of  experiments 23 

Experiments  on  immediate  submergence  after  seeding 24 

Effect  of  sowing  broadcast  on  the  soil 25 

Effect  of  sowing  broadcast  in  the  water 26 

Effect  of  drilling  seed 26 

Effect  of  irrigating  drilled  check  plots  in  the  ordinary  way 26 

Conclusions 26 

Comparison  of  air  and  water  temperatures 27 

Experiments  on  submergence  after  the  rice  has  emerged 28 

Broadcasting  and  drilling  seed  compared 28 

Spring  plowing  and  disking  of  stubble  compared... 30 

Experiments  on  rate  of  seeding  and  method  of  irrigation 33 

Experiments  on  seedbed  preparation 33 

Effect  of  good  preparation 34 

Effect  of  no  preparation 35 

Control  of  cat-tail  by  heavy  seeding 35 

Conclusions 35 

Experiments  on  rates  of  seeding  with  three  varieties 35 

Summary 38 

*  The  rice  investigations  conducted  at  Cortena,  Colusa  County,  are  admin- 
istered by  the  Division  of  Irrigation  Investigations  and  Practice  of  the  College 
of  Agriculture  with  the  assistance  and  advice  of  the  following  rice  committee 
appointed  by  the  Director  of  the  Agricultural  Experiment  Station:  Frank 
Adams,  chairman,  P.  L.  Hibbard,  J.  W.  Jones,  Superintendent  Biggs  Rice  Field 
Station  of  the  Bureau  of  Plant  Industry,  P.  B.  Kennedy,  W.  W.  Mackie,  Chas. 
F.  Shaw,  and  W.  W.  Weir.  During  1923,  Messrs.  Louis  Rathbun,  George  Houx, 
and  Raymond  Houx,  rice  growers,  were  especially  helpful  with  suggestions  and 
in  the  loaning  of  equipment.  As  during  the  previous  season,  irrigation  water  was 
furnished  free  by  the  Glen-Colusa  Irrigation  District,  and  Carroll  F.  Dunshee 
continued  in  immediate  charge. 

The  investigations  conducted  at  the  Biggs  Rice  Field  Station  are  planned, 
financed,  and  directed  by  the  Office  of  Cereal  Investigations  of  the  Bureau  of 
Plant  Industry,  U.  S.  Department  of  Agriculture,  and  are  conducted  by  Jenkin 
W.  Jones,  Agronomist. 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  California,  Davis  Libraries 


http://www.archive.org/details/resultsofriceexp375duns 


INTRODUCTION 

Water  grass  (Echinochloa  crus-galli  and  varieties)  is  the  most 
troublesome  weed  in  the  California  rice  fields.  This  grass  was  present 
in  California  when  the  rice  industry  first  started,  and  has  spread  from 
year  to  year  in  spite  of  efforts  both  by  hand-pulling  and  by  cultural 
practices,  to  keep  it  under  control.  The  conditions  under  which  rice 
is  grown  in  California  are  almost  ideal  for  the  growth  and  distribution 
of  water  grass.  Not  only  does  this  grass  reproduce  rapidly,  but  its 
seeds  are  inclosed  by  oily  hulls  which  tend  to  protect  them  against 
unfavorable  climatic  conditions. 

Rice  land  in  California  is  spoken  of  as  either  "new"  or  "old" 
land.  New  land  is  that  which  has  never  been  seeded  to  rice.  Old  land 
is  that  which  has  produced  two  or  more  rice  crops.  Practically  all, 
if  not  all,  of  the  old  lands — and  these  constitute  the  major  portion  of 
the  rice  acreage — are  quite  foul  with  water  grass. 

On  this  foul  land  it  is  practically  impossible  to  grow  profitable  rice 
crops  by  the  old  method  of  irrigation.  This  consists  of  irrigating  and 
draining  the  land  at  frequent  intervals  until  thirty  days  after"  the  rice 
has  emerged.  The  land  is  then  submerged  about  six  inches,  the  water 
being  held  at  that  depth  until  the  fields  are  drained  for  harvest.  Under 
this  method  of  irrigation  on  foul  land,  the  water  grass  competes 
successfully  with  the  rice  crop,  and  the  reduced  yields  which  follow 
are  often  unprofitable. 

Rice  growers  observed  a  few  years  ago  that  water  grass  was  con- 
trolled or  suffocated  to  a  marked  extent  by  water  if  the  young  plants 
or  seed  were  completely  submerged  for  some  time.  At  the  same  time 
they  noticed  that  rice  seed  germinated  under  water  and  that  the  young 
seedlings  stretch  upward  through  the  water  and  later  make  a  normal 
growth.  These  observations  led  to  new  methods  of  irrigation  for  rice 
when  grown  on  foul  land. 

The  first  of  the  new  methods,  and  the  most  common,  consists  of 
sowing  the  rice  broadcast  on  a  smooth  seedbed  and  immediately  sub- 
merging the  land  four  to  eight  inches.  The  water  is  held  at  this  depth 
until  the  land  is  drained  for  harvest. 

The  second  method  consists  of  preparing  a  reasonably  smooth  seed- 
bed, submerging  the  land  to  a  depth  of  four  to  eight  inches,  and  then 
sowing  the  rice  broadcast  in  the  water,  which  is  held  at  the  depth 
named  until  the  land  is  drained  for  harvest. 


6  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION 

A  third  method,  which  is  much  less  common,  consists  of  drilling  or 
broadcasting  the  rice.  The  land  is  immediately  irrigated  and  then 
drained.  It  remains  thus  until  the  rice  and  water  grass  seedlings 
emerge.  Then  the  land  and  the  young  seedlings  are  submerged  four  to 
eight  inches,  the  water  being  held  at  that  depth  until  the  land  is 
drained  for  harvest. 

Of  these  three  methods  of  irrigation,  the  first  and  second  are  quite 
effective  in  the  control  of  the  common  water  grasses.  The  third  is  less 
effective.  The  first  method  is  used  most  extensively  on  old  rice  land 
in  California.    It  has  been  used  by  some  growers  for  several  years. 

This  bulletin  gives  the  results  of  investigations  and  experiments  on 
water  grass  control  and  related  subjects  conducted  by  this  Station  at 
Cortena,  Colusa  County,  during  the  season  of  1923,  and  the  results  of 
experiments  on  water  grass  control  conducted  by  the  Office  of  Cereal 
Investigations,  Bureau  of  Plant  Industry,  United  States  Department 
of  Agriculture,  at  the  Biggs  Rice  Field  Station  during  the  seasons  of 
1922  and  1923.  While  these  investigations  have  been  conducted 
separately,  the  work  at  the  two  field  stations  has  been  correlated  in 
such  a  way  as  to  eliminate  unnecessary  duplication.  For  all  practical 
purposes,  therefore,  the  work  at  the  two  stations  constitutes  one  study, 
and  the  results  obtained  can  appropriately  be  published  in  a  single 
bulletin.  This  has  been  made  possible  through  a  cooperative  under- 
standing between  the  California  Agricultural  Experiment  Station  and 
the  Bureau  of  Plant  Industry. 


I.    RESULTS  OF  RICE  EXPERIMENTS  AT  CORTENA 

IN   1923 

By  CARROLL  F.  DUNSHEE 


This  progress  report  of  rice  experiments  carried  on  during  the  crop 
season  of  1923  by  the  University  of  California  College  of  Agriculture 
at  the  temporary  field  station  near  Cortena,  Colusa  County,  covers 
work  which  was  in  the  main  a  continuation  of  that  started  in  1922,  a 
progress  report  of  which  appeared  as  Bulletin  354  of  the  University  of 
California  Agricultural  Experiment  Station. 

Two  new  lines  of  work  were  started  in  1923,  one  being  to  determine 
the  water  requirements  of  rice,  and  the  other  to  determine  the  best 
follow-crops  for  rice.  C.  F.  Shaw  has  continued  his  studies  on  the 
effect  of  rice-growing  on  the  physical  condition  of  the  soil  and  P.  L. 
Hibbard  has  studied  the  effect  of  rice-growing  on  the  soil  bacteria. 


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i  49   \44  ■":>XX>. 


Fig.  1. — Map  of  temporary  rice  experiment  station,  Cortena,  showing 
arrangement  and  location  of  plots. 


UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 


PREPARATION  OF  FIELD  AND  SEEDING 

The  field  preparation  and  the  method  of  seeding  were  the  same  as 
practiced  in  1922.  Caloro  seed  was  used,  however,  in  place  of  Early 
Wataribune.  The  standard  rate  of  seeding  was  150  pounds  to  the  acre. 
Two  plots,  however,  were  seeded  at  the  rate  of  200  pounds  to  the  acre, 
and  two  plots  were  submerged  and  seeded  in  the  water  at  the  rate  of 
135  pounds  to  the  acre.  Plots  not  requiring  submergence  at  a  later 
date  were  submerged  by  May  1. 


EFFECT  OF  METHOD  OF  SEEDING  AND  SUBMERGENCE  ON 
WATER  GRASS  CONTROL 

Submergence  immediately  after  broadcasting. — During  1922  the 
plots  in  this  series  of  experiments  were  submerged  to  depths  of  two, 
four,  six,  and  eight  inches.  It  was  found  impracticable  to  submerge 
plots  to  a  depth  of  two  inches ;  therefore,  this  treatment  was  abandoned 
in  1923  and  two  ten-inch  submergence  plots  substituted. 

A  somewhat  different  problem  was  encountered  this  season  in  that 
three  inches  of  rain  fell  between  March  31  and  April  9,  after  the  seed- 
bed had  been  fully  prepared.  This  rain  caused  considerable  barnyard 
grass  (Echinochloa  crus-galli)  and  other  water  grasses  to  sprout, 
making  it  necessary  to  double  disk  the  field  before  seeding.  This  disk- 
ing killed  most  of  the  sprouted  water  grass  seeds,  but  those  not  killed 
in  this  way  were  found  to  be  very  difficult  to  control.  This  experience 
added  weight  to  the  impression  that  it  is  difficult  to  control  barnyard 
grass  by  continuous  submergence  after  it  has  established  roots  in  the 
soil. 

In  plots  submerged  ten  inches,  no  barnyard  grass  appeared  above 
the  surface  of  the  water.  The  plots  submerged  eight  inches  had  a  few 
scattering  plants ;  those  submerged  six  inches,  a  much  larger  number, 
though  not  enough  to  influence  the  yield,  while  those  submerged  four 
inches  were  quite  foul.  It  was  found  impossible  to  control  the  small 
sedge  or  Umbrella  plant  (Cy  perns  difformisf).  This  was  considered 
very  troublesome  in  1922  and  spread  so  this  past  season  that  it  was 
present  in  all  plots.  It  was  estimated  that  the  yield  of  several  of  the 
plots  was  reduced  as  much  as  50  per  cent  by  this  weed.  In  fact,  the 
great  reduction  in  yield  this  season  is  believed  to  be  due  largely  to  its 
presence,  since  excellent  stands  of  rice  were  obtained  in  all  plots  up 
to  the  time  the  sedge  began  to  show  its  effect  about  June  15. 


Bulletin  375] 


RICE   EXPERIMENTS 


Broadcasting  in  water. — The  effect  on  weed  control  was  the  same 
as  in  the  plots  submerged  after  broadcasting. 

Submergence  immediately  after  drilling. — A  very  poor  stand  of 
rice  resulted  from  this  treatment.  There  was  complete  control  of  the 
barnyard  grass  in  plots  submerged  eight  inches.  Some  grass,  however, 
appeared  in  the  plots  submerged  six  inches,  and  considerably  more 
in  plots  submerged  four  inches.  The  stand  of  sedge  in  all  these  plots 
was  exceptionally  thick.  It  seems  clear,  therefore,  that  a  poor  stand  of 
rice  is  favorable  to  the  growth  of  sedge. 


Fig.  2. — Beginning  of  submergence  of  rice  plots. 


Submergence  after  germination. — In  this  experiment  the  seed  was 
drilled  in  and  the  plants  submerged  to  the  required  depth  when  they 
were  about  one  inch  high.  Good  stands  of  rice  were  obtained  in  all 
plots  up  to  the  time  of  submergence.  Later,  however,  the  plots  became 
foul  with  barnyard  grass,  and  at  maturity  the  stand  of  rice  was  poor. 
The  sedge  was  as  thick  in  these  plots  as  in  those  broadcasted  and  then 
submerged. 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


TABLE   1 

Summary  of  Results  Showing  Effects  of  Methods  of  Seeding  and  Depths  of 
Submergence  on  Weed  Control  and  Yields  of  Rice 


Plots 

Seeding 

Submergence 

Acre-yields  in 
pounds 

Compared 
with  checks 

Date 

Method 

Date 

Depth, 

inches 

1922 

1923 

Aver- 
age 

Gain 

Loss 

60,41 

May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 
May  1 

Broadcast  on  soil 

Broadcast  on  soil 

Broadcast  on  soil 

Broadcast  on  soil 

Broadcast  in  water 

Broadcast  in  water 

Broadcast  in  water 

Drilled 

Drilled 

Drilled 

Drilled 

Drilled 

Drilled 

Drilled 

May    1 
May    1 
May    1 
May    1 
May    1 
May    1 
May    1 
May    1 
May    1 
May    1 
May  26a 
May  26° 
May  26a 
June  20 

10 

8 
6 
4 
8 
6 
4 
8 
6 
4 
8 
6 
4 
6 

1765 

1871 

1841 

1448 

2042 

1583 

1591 

15S8 

1442 

709 

1423 

1045 

966 

924 

630 
1183 
1444 

955 
1112 

677 
1136 

823 

471 
77 

647 

58,44 

2766 

3318 
2733 
2453 
2041 
2952 
2358 
1770 
1716 
2142 
1079 
1368 
1347 

2318 
2579 
2090 
2247 
1812 
2271 
1958 
1606 
1212 
1782 
1062 
1167 
1135 

57,45 

53,47 

59,50 

55,40 

55,46 

54,49 

51,48 

52,39 

33,42 

34,35 
36,37 

73 

32 
Ch'k 

6a,38& 

Seeding  was  at  the  rate  of  150  pounds  per  acre 
°  Plots  irrigated  twice  and  submerged  when  about  one  inch  high. 
&  First  irrigation  on  May  3,  followed  by  four  irrigations  prior  to  submergence 

thirty  days  after  emergence  of  the  plants.     These  plots  were  exceedingly  foul 

with  rice  weeds. 


Fig.  3. — Arrowhead  (Sagittaria  latifolia).  This  weed  is  not  troublesome  in 
good  stands  of  rice,  being  found  in  thin  stands  and  in  irrigation  ditches.  Con- 
tinuous submergence  does  not  control  it.    Summer  fallow  aids  in  its  control. 


Bulletin  375] 


RICE   EXPERIMENTS 


11 


EFFECT   OF  DATE   OF  SEEDING  AND   SUBMERGENCE   ON 
WATER  GRASS  CONTROL  AND  YIELDS  OF  RICE 

On  account  of  late  spring  rains,  the  earliest  seeding  practicable  in 
1923  was  April  25  instead  of  April  15,  as  planned.  Somewhat  better 
yields  seem  to  have  been  obtained  from  this  early  seeding  than  from 
seeding  on  May  1  and  May  15.  Distinctly  better  yields  were  obtained 
from  the  earlier  seeding  than  from  that  on  June  1.  The  only  difference 
noted  in  weed  control  was  that  the  sedge  was  considerably  thicker  in 
plots  submerged  June  1.    Resulting  yields  are  presented  in  table  2. 

TABLE  2 

Summary  of  Results  of  Experiments  on  the  Date  of  Seeding  and 

Submergence  of  Rice 


Seeding 

Submergence 

Acre-yields  in  pounds 

Plots 

Date 

Method 

Date 

Depth, 
inches 

1922 

1923 

Average 

1,20 
6,19 
14,16 

13, 176 

April  25° 
May     1 
May  15 
June     1 

Broadcast  on  soil 
Broadcast  on  soil 
Broadcast  on  soil 
Broadcast  on  soil 

April  25 
May     1 
May  15 
June     1 

6 
6 

6 

6 

3664 

2558 
2648 
2069 

2788 
2338 
2388 
1137 

3226 
2448 
2518 
1603 

a  April  15  in  1922. 

6  Yields  in  plots  13  and  17  reduced  materially  in  1923  by  annual  sedge. 


Fig.  4. — Sprangle  top  (Leptochloa  fasicularis) .  Can  be  controlled  by  con- 
tinuous submergence.  Where  not  controlled  it  is  a  serious  pest.  Grows  two  to 
four  feet  high.    Matures  seed  in  September. 


12 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


MISCELLANEOUS  EXPERIMENTS 

In  all  plots  concerned  in  these  experiments  submergence  was  com- 
pleted by  May  1.  Unless  otherwise  noted,  seeding  was  at  the  rate  of 
150  pounds  per  acre. 

Weed  and  cat-tail  control  by  heavy  seeding. — Very  thick  stands  of 
rice  resulted  from  broadcasting  at  the  rate  of  200  pounds  to  the  acre 
and  submerging  to  a  depth  of  six  inches.  There  was  no  control  of  cat- 
tails, but  there  was  a  slight  control  of  the  sedge.  Barnyard  grass 
control  was  similar  to  that  in  other  continuous  submergence  plots. 


Fig.  5. — Joint  grass  (Paspalum  distchum).  This  weed  is  becoming  a  menace, 
especially  in  old  rice  fields  and  in  ditches.  It  usually  starts  in  the  unplowed 
portions  of  fields.  Continuous  submergence  does  not  control  it.  Can  be  held  in 
check  by  deep  plowing  and  fallow.  The  stalk  is  usually  one  to  two  feet  high. 
Matures  seed  in  September. 

Seed  broadcasted  on  rice  stubble. — Very  poor  stands  resulted  from 
this  treatment.  Weed  and  cat-tail  growth  .became  very  thick  and  by 
the  time  the  crop  was  mature  it  was  impossible  to  use  a  binder. 

Seed  broadcasted  in  water  on  rice  stubble. — The  stand  resulting 
from  this  treatment  was  similar  to  that  in  other  plots  which  were  not 
plowed.  Because  of  cat-tail  and  other  weed  growth  it  was  imprac- 
ticable to  harvest  the  crop. 

Rice  after  fallow. — These  plots  had  been  in  rice  continuously  for 
four  years  previous  to  1922,  but  were  fallowed  that  year.  They  were 
plowed  in  the  spring  of  1922  and  again  in  March  of  1923.  Excellent 
seedbeds  resulted  from  this  last  plowing.     The  rice  was  broadcasted 


Bulletin  375] 


rice;  experiments 


13 


and  the  plots  submerged  immediately  to  a  depth  of  six  inches.  Poor 
stands  were  obtained  in  all  plots.  There  was  only  a  scattering  of  barn- 
yard grass,  but  sedge,  red  stem  (Ammania  coccinea),  and  sprangle-top 
(Leptochloa  fascicularis)  were  very  prevalent. 

Rice  broadcasted  in  water  at  the  rate  of  135  pounds  to  the  acre. — In 
1922  it  was  observed  that  rice  broadcasted  in  water  at  the  rate  of  150 
pounds  per  acre  gave  stands  that  were  perhaps  too  thick  for  maximum 
yields.  Therefore,  in  1923,  two  plots  were  submerged  and  the  seed 
broadcasted  at  the  rate  of  135  pounds  to  the  acre.  The  sedge  reduced 
the  yields  in  all  treatments  to  such  an  extent  that  it  was  impossible  to 
note  any  difference  between  the  two  rates  of  seeding. 


Pig.  6. — Barnyard  grass  or  water  grass  (Echinochloa  crus-galli) .  This  shows 
the  late  form  of  barnyard  grass.  It  is  yellowish-white  in  color  and  matures 
seed  late  in  September.  The  plant  grows  one  to  three  feet  high.  It  is  the  most 
difficult  form  of  Echinochloa  crus-galli  to  control. 


WATER  REQUIREMENTS  OF  RICE  PLANTS 

In  order  to  gain  information  on  the  water  requirements  of  the  rice 
plant,  experiments  were  started  to  determine  the  amount  of  water  lost 
through  evaporation,  through  seepage  in  the  soil,  and  by  transpiration 
through  the  leaves.  An  area  25  by  50  feet  was  leveed  off  from  the  rest 
of  the  field,  and  nine  concrete  tanks  thirty  inches  in  diameter  and 
four  feet  deep  were  placed  in  the  soil.  All  of  these  tanks  were  painted 
on  the  inside  with  a  waterproof  paint,  and  with  the  exception  of  two 
tanks  used  for  seepage  determinations,  were  sealed  at  the  bottom  with 
three  inches  of  concrete.    One  tank,  which  was  so  sealed  at  the  bottom, 


14 


UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 


but  in  which  no  rice  was  planted,  was  used  for  an  evaporation  tank. 
Two  tanks,  having  the  bottoms  sealed,  were  planted  with  rice  and  used 
to  determine  the  amount  of  moisture  lost  by  transpiration  and 
evaporation.  Two  tanks,  having  the  bottoms  sealed  and  the  tops 
covered  with  celluloid,  were  planted  with  rice  and  used  to  determine 
the  loss  by  transpiration.     The   area  surrounding  these   tanks  was 

TABLE  3 

Summary  of  Results  of  Miscellaneous  Experiments 


Treatment0 

Acre-yields  in  pounds 

1922 

1923 

Average 

2,5 

Seed  broadcasted  at  rate  of  200  pounds  per  acre 
and  submerged  six  inches  in  effort  to  control 
weed  and  cat-tail  growth 

1994 

2331 

2162 

15,21 

Seed  broadcasted  on  stubble  and  submerged  six 
inches 

1728 

b 

864 

12,18 

Rice  stubble  submerged  six  inches  and  seed  broad- 
casted in  water 

1139 

b 

569 

23,43 

Seed  broadcasted  in  six  inches  of  water  at  rate  of 
135  pounds  per  acre 

1568 

7,9,11 

Seed  broadcasted  and  submerged  six  inches  after 
fallow  in  1922 

1210 

22,24-30, 
61 

Seed  broadcasted  and  immediately  submerged  six 
inches 

2312 

1895 

2103 

a  Seeding  and  submergence  completed  on  May  3.     Unless  otherwise  noted 
seeding  was  at  the  rate  of  150  pounds  per  acre. 

6  Cat-tail  and  other  foul  growth  made  it  impracticable  to  cut  rice. 


seeded  with  rice  and  submerged,  in  order  to  simulate  field  conditions. 
Water  was  measured  into  the  tanks  from  day  to  day  during  the  grow- 
ing season.  Two  tanks  were  used  in  an  effort  to  determine  the  value 
of  copper-sulfate  in  the  control  of  scum  or  algae,  but  the  waterproof 
coating  applied  to  the  tanks,  or  some  other  condition,  prevented  algal 
growth.  These  experiments  must  necessarily  be  continued  for  some 
time  before  definite  conclusions  can  be  drawn.  Mention  of  them  is 
made  here  merely  to  indicate  to  growers  the  type  of  studies  under  way 
in  addition  to  those  for  which  results  are  given. 


Bulletin  375] 


RICE   EXPERIMENTS 


15 


The  low  temperatures  during  the  early  part  of  the  growing  season 
in  1923  may  be  responsible  for  part  of  the  low  yields  obtained  at 
Cortena  and  throughout  the  valley.  Both  the  maximum  and  minimum 
temperatures  were  considerably  lower  than  during  the  same  period  in 
1922.  This  may  have  kept  the  plants  from  being  as  thrifty  as  they 
would  have  been  with  higher  temperatures. 

TABLE  4 
Monthly  Average  of  Maximum  and  Minimum  Temperatures*  at 
Cortena,  California 


Month 


March 

April 

May  1-11... 
May  12-31 

June 

July 

August 

September. 
October 


1922 


Maximum 


85.50 
90 .  13 
93.84 
90.74 
92.96 
73.03 


Minimum 


58.00 
61.20 
66.96 
50.67 
55.88 
50.67 


1923 


Maximum 


70.29 
69.69 
82.18 
78.95 
83.50 
92.74 
91.54 
87.30 
77.38 


Minimum 


42.58 
48.10 
51.90 
51.50 
57.30 
63.60 
62.70 
60.33 
53.70 


*  Recording  of  temperatures  started  May  12,  1922. 

EXPERIMENTS  WITH  FIELD  CROPS 

Thirteen  varieties  of  field  crops  were  planted  on  land  which  had 
been  in  rice  continuously  for  four  years  but  which  had  been  fallowed 
in  1922.  Owing  to  the  fact  that  the  method  of  irrigation  followed 
proved  to  be  faulty,  satisfactory  results  were  not  obtained.  These 
trials  will  be  resumed  in  1924  under  more  favorable  cultural 
conditions. 


STUDIES  OF  THE  PHYSICAL  CONDITIONS  OF  RICE  SOILS* 

Studies  were  continued  through  the  year  on  the  physical  character 
of  the  Willows  clay  and  Stockton  clay  adobe,  comparisons  being  made 
between  soils  taken  from  fields  that  had  been  in  rice  for  some  years  and 
fields  that  had  never  been  in  rice  or  in  any  irrigated  crop.  These 
studies  showed  the  same  inconclusive  results  as  those  carried  out  last 
year ;  no  evidence  has  as  yet  been  obtained  to  show  that  any  material 


*  Charles  F.  Shaw  of  the  Division  of  Soil  Technology  furnished  this  brief 
progress  report. 


16  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 

change  has  been  brought  about  in  the  physical  character  of  the  soil 
through  the  submergence  incidental  to  rice  culture. 

In  an  endeavor  to  determine  the  amount  of  expansion  and  con- 
traction that  brings  about  the  shrinking,  cracking,  and  granulation 
that  occur  on  these  soils,  expansion  studies  were  made  using  the 
auxographic  method  devised  by  the  Arizona  Experiment  Station.  The 
results  showed  that  the  Willows  clay,  which  had  produced  a  rice  crop, 
had  a  more  rapid  expansion  than  the  same  soil  which  had  never  been 
irrigated.  The  total  amount  of  expansion,  however,  was  found  to 
be  somewhat  greater  in  the  unirrigated  lands.  The  studies  of  the 
Stockton  clay  adobe  from  Biggs  showed  the  opposite  effect,  the  rate 
of  expansion  of  the  soils  from  the  rice  plots  being  slower,  but  the  total 
amount  greater  than  that  of  the  samples  from  the  Experiment  Station 
yard  which  had  never  been  in  rice. 

Mechanical  analyses  are  being  made  by  a  new  method  which  shows 
the  amounts  of  the  finest  clay  particles  in  the  soil.  The  results  to 
date  appear  to  be  as  inconclusive  and  contradictory  as  those  on 
expansion  and  contraction  measurements  and  those  reached  last  year. 
In  short,  there  is  no  positive  experimental  evidence  to  show  that  rice 
culture  has  caused  any  measurable  change  in  the  physical  character 
of  these  soils. 


CHEMICAL  STUDIES  ON  WATERS  AND  SOILS* 
A.   WATER  BEFORE  AND  AFTER  USE  ON  RICE 

(1)  On  the  experiment  plots  at  Cortena. — The  canal  water,  prima- 
rily derived  from  the  Sacramento  River,  was  nearly  constant  in  com- 
position throughout  the  season.  It  contained  slightly  more  salts  at  the 
end  of  the  summer  than  in  the  spring.  The  water  draining*  from  the 
rice  plots  contained  somewhat  more  salts  than  the  canal  water,  and 
it  also  changed  very  little  during  the  season.  It  was  at  all  times  of 
good  quality  for  irrigation  purposes.  Evidently  the  salts  in  the  soil 
were  not  near  enough  to  the  surface  to  be  measurably  absorbed  by  the 
water  that  flowed  over  the  fields. 

(2)  On  commercial  rice  fields  near  Cortena. — The  water  supplied 
to  these  fields  was  from  the  same  canal  which  supplied  the  experi- 
mental plots  at  Cortena.    In  some  places,  the  drainage  was  similar  to 

*  The  report  of  rice  investigations  at  Cortena  in  1922,  published  as  Bulletin 
354  of  this  Station,  contained  a  preliminary  report  on  water  and  soil  analyses 
by  P.  L.  Hibbard  of  the  Division  of  Plant  Nutrition.  A  complete  report  on 
these' studies,  together  with  a  report  by  the  same  author  on  changes  of  bacterial 
flora  in  rice  soils,  is  included  herewith. 


Bulletin  375]  RICe  EXPERIMENTS  17 

that  at  Cortena,  though  in  all  cases  it  contained  somewhat  more  soluble 
matter.  But  the  drainage  from  other  fields  contained  five  to  ten  times 
as  much  soluble  matter  as  the  intake  water.  Generally  the  highest 
amounts  of  salts  in  the  drainage  were  found  in  the  early  part  of  the 
season.  In  other  words,  the  first  run-off  carried  away  most  of  the 
soluble  salts  that  were  near  enough  to  the  surface  of  the  land  to  be 
affected  by  the  rice  flooding.  Consequently,  as  the  season  advanced, 
the  drainage  water  contained  less  and  less  soluble  matter. 

(3)  On  rice  fields  in  Sutter  Basin. — By  the  assistance  and  courtesy 
of  the  Sutter  Basin  Company,  water  samples  were  taken  throughout 
the  season  from  the  intake  at  Sacramento  River,  from  their  main 
drain,  and  from  the  inlet  and  outlet  in  certain  rice  fields. 

The  river  water  was  essentially  the  same  as  that  at  Cortena,  show- 
ing a  very  slight  increase  of  soluble  matter  during  the  summer.  The 
outflow  water  at  the  main  drain  carried  much  more  soluble  salts  than 
that  at  Cortena,  but  it  showed  the  same  sort  of  decrease  in  soluble 
matter  toward  the  end  of  the  season,  when  it  contained  about  one-third 
as  much  as  at  the  beginning  of  irrigation. 

The  water  on  and  off  certain  individual  rice  fields  showed  the  same 
general  changes  as  were  observed  near  Cortena,  nearly  uniform  com- 
position of  the  intake  water,  and  a  gradual  lessening  of  the  amount 
of  salts  in  the  drainage  water  as  the  season  advanced.  Rather  large 
variations  were  recorded  in  the  composition  of  the  drainage  waters  of 
these  fields  from  week  to  week,  being  sometimes  higher,  and  sometimes 
lower  in  salts.  These  sharp  changes  may  have  been  caused  by  variations 
in  the  weather  and  by  variations  in  amounts  of  water  used. 

Cause  of  the  increase  of  salts  in  the  drainage  water  over  the  amount 
in  the  intake  water. — The  drainage  waters  in  all  places  and  at  all  times 
carried  more  soluble  matter  than  the  water  going  on  the  land.  Part 
of  this  increase  was  due  to  concentration  by  evaporation,  but  most  of 
it  must  be  attributed  to  substances  dissolved  out  of  the  soil.  As  most 
of  these  soils  are  known  to  have  contained  alkali  salts  before  rice 
culture  was  begun,  it  was  to  be  expected  that  water  passing  over  them 
would  carry  away  some  of  those  salts.  Since  some  of  the  salts  are 
objectionable,  the  land  is  to  that  extent  improved  by  the  rice  culture. 

General  character  of  the  salts  in  the  waters. — The  Sacramento 
River  water  contains  small  amounts  of  the  bicarbonates  of  calcium  and 
magnesium,  a  little  sodium  chloride,  much  less  sodium  sulfate,  and  a 
little  sodium  bicarbonate.  The  last  named  salt  determines  the 
character  of  the  water.  It  has  primary  alkalinity,  the  usual  quality 
of  water  from  regions  of  primary  rocks  such  as  granites  or  others 


18  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION 

having  a  considerable  amount  of  the  silicates  of  sodium  or  potassium. 
Such  water,  when  evaporated  to  dryness,  leaves  an  easily  soluble 
residue  of  sodium  carbonate,  the  so-called  black  alkali,  which  is  very 
undesirable  in  soil.  However,  the  amount  of  it  in  Sacramento  River 
water  is  so  small  that  it  is  relatively  harmless. 

The  drainage  waters  from  these  lands  contain  very  little  sodium 
sulfate,  a  fairly  large  amount  of  the  bicarbonates  of  calcium,  mag- 
nesium, and  sodium,  and  generally  considerable  sodium  chloride,  with 
calcium  and  megnesium  chlorides  sometimes.  The  chlorides  are  the 
most  variable  constituents  of  these  drainage  waters;  since  they  are 
largely  derived  from  the  soils  over  which  the  waters  flow,  variation 
is  to  be  expected. 


B.    CHANGES   PRODUCED   IN   THE   ALKALI    CONTENT   OF    THE   SOILS    BY    THE 
IRRIGATION  WATER  USED  ON  RICE 

(1)  On  the  experiment  plots  at  Cortena. — Samples  of  soil  were 
taken  before  planting  and  after  harvest  from  as  nearly  the  same 
locations  as  possible.  Most  of  them  were  taken  to  four  feet,  but  some 
were  taken  down  to  twelve  feet.  Each  foot  was  kept  and  analyzed 
separately.  Samples  were  also  taken  from  an  adjoining  field  supposed 
never  to  have  been  in  rice  or  to  have  been  flooded.  There  was  con- 
siderable variation  in  the  amounts  of  salts  in  the  samples  from 
different  holes  on  both  old  and  new  land.  In  some  places  there  was 
little  in  either,  but  in  general  there  was  more  saline  matter  in  the 
surface  two  feet  of  the  new  land  than  in  a  similar  portion  of  the  old 
land.  Below  the  fourth  foot  there  were  similar  amounts  in  both.  But 
in  view  of  the  variability  of  these  soils,  it  seems  unwise  to  consider  that 
the  number  of  samples  taken  was  sufficient  to  show  the  true  com- 
position of  these  soils.  Hence  it  is  not  safe  to  assume  that  the  amount 
and  kinds  of  salts  in  the  different  plots  were  originally  the  same.  On 
the  other  hand,  we  have  no  means  other  than  this  comparison  of  new 
and  old  soils  to  show  the  effect  of  the  rice  culture  on  the  salts. 

In  most  parts  of  the  old  land,  there  is  little  alkali  and  not  much 
salt  in  the  upper  two  feet,  and  with  one  exception,  little  difference  in 
the  samples  taken  before  planting  and  after  harvest.  In  cases  where 
there  were  notable  amounts  of  chlorides  near  the  surface  before  plant- 
ing, the  after-harvest  samples  showed  similar  concentrations  one  or 
two  feet  lower  in  the  soil  with  a  corresponding  reduction  near  the 
surface.  This  change  in  location  of  the  salts  is  regarded  as  being  due 
to  the  leaching  effect  of  the  irrigating  water.     Samples  taken  before 


Bulletin  375]  RICE  EXPERIMENTS  19 

and  after  the  season,  from  four  feet  down  to  twelve  feet,  were  as 
nearly  alike  as  samples  taken  at  different  times  could  be  expected  to 
be.  There  was  no  evidence  of  leaching  below  the  fourth  foot.  It  seems 
probable  that  the  irrigating  water  of  previous  years  had  already 
removed  most  of  the  salts  from  the  upper  two  or  three  feet  of  these 
soils,  before  this  season's  work  was  started;  also,  that  the  flooding 
incident  to  rice  culture  will  only  very  slowly  remove  the  salts  from 
the  deeper  portions  of  these  tight  clay  soils.  Whether  these  lower 
layers  of  saline  matter  will  come  to  the  surface  if  the  soil  is  again  used 
for  crops  other  than  rice  cannot  now  be  foretold.  If  such  rise  of 
alkali  should  occur,  it  is  probable  that  another  period  of  rice  culture 
with  flooding  would  carry  away  much  of  the  alkali  and  leave  the  soil 
more  free  of  salts. 

It  is  concluded  that  in  these  clay  soils,  most  of  the  salts  removed 
by  rice  culture  are  carried  away  in  the  surface  run-off,  rather  than  in 
the  underground  drainage. 

(2)  On  rice  lands  in  Glenn  County. — Many  samples  of  soil  from 
rice  lands  near  Princeton  and  Deleven  were  taken  in  December,  1921. 
Though  these  samples  varied  greatly  from  one  hole  to  another,  it  is 
plain  that  in  many  places  there  were  very  small  amounts  of  salts  in 
the  surface  one  to  two  feet,  and  a  larger  quantity  of  salts  lower  down. 
These  lands  have  been  flooded  during  two  or  three  previous  years  of 
rice  culture.  The  soils  are  similar  to  those  at  Cortena  and  the  analyses 
indicate  similar  effects  produced  by  rice  flooding.  One  notable  differ- 
ence is  in  the  large  amount  of  sulfates  in  the  Glenn  County  soils,  as 
compared  with  the  very  small  amount  of  sulfates  in  the  Cortena  soils. 

(3)  On  lands  in  rice  in  Imperial  Valley. — These  soils  are  cal- 
careous silts  very  much  more  pervious  to  water  than  the  clays  of  the 
Colusa  and  Glenn  County  rice  fields.  This  difference,  in  perviousness 
has  produced  very  different  effects  where  irrigation  by  flooding  has 
been  practiced.  Soil  samples  were  taken  before  planting  and  after 
harvest,  to  six-foot  depths,  each  foot  being  tested  separately.  There 
was  no  run-off  from  this  soil,  so  that  the  only  possible  movement  of 
water  was  downward.  Samples  of  water  from  the  surface  of  the  plots 
varied  little  from  the  water  supplied  to  the  plots,  so  that  the  changes 
produced  must  be  ascribed  to  leaching.  The  soil  had  not  recently 
been  flooded.  It  contained,  before  planting,  large  amounts  of  sulfates 
and  chlorides,  somewhat  uniformly  distributed  throughout  the  upper 
six  feet.  The  samples  taken  after  harvest  had  little  chloride  in  the 
first  four  feet,  and  little  sulfate  in  the  first  two  feet.  But  there  was 
some  increase  in  the  amount  of  these  salts,  particularly  in  sulfates, 


20  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

at  a  depth  of  five  and  six  feet.  In  some  cases,  the  chlorides  seem  to 
have  been  carried  down  below  the  sixth  foot.  The  sulfate  was  carried 
along  much  more  slowly  by  the  leaching  water. 

From  these  results,  it  sems  probable  that  the  flooding  incident  to 
rice  culture  would,  in  two  or  three  years,  carry  the  alkali  salts  in  these 
soils  so  far  below  the  surface  that  they  would  not  again  be  troublesome 
to  ordinary  crops  and  perhaps  not  to  trees. 


C.    GENERAL  CONCLUSIONS  REGARDING  WATERS  AND  SOILS 

(1)  The  irrigating  water  from  the  Sacramento  River  is  of  good 
quality  and  varies  little  throughout  the  season. 

(2)  Drainage  from  rice  fields  which  have  been  flooded  for  two  or 
more  years  is  likely  to  be  of  fairly  good  quality  for  irrigation.  But 
if  the  soil  contains  much  alkali  or  salts  within  two  feet  of  the  surface, 
some  or  much  of  these  soluble  substances  will  be  carried  off  in  the 
drainage,  so  that  sometimes  it  may  be  unsuitable  for  irrigation. 

(3)  Considering  the  fact  that  rice  is  relatively  tolerant  of  saline 
water,  it  seems  feasible  to  use  drainage  from  one  field  to  irrigate  the 
next  lower  field,  and  so  on  until  the  final  drainage  becomes  too  saline 
for  use. 

(4)  There  seems  to  be  little  percolation  of  the  water  down  through 
the  clay  soils,  so  that  salts  in  those  soils  two  feet  or  more  below  the 
surface  will  be  removed  only  very  slowly  by  the  flooding  practiced  in 
rice  culture.  In  more  easily  penetrated  silts  or  sand  there  is  sufficient 
percolation  of  the  water  to  carry  away  most  of  the  objectionable  salts 
from  the  region  of  plant  roots  into  the  under  drainage  within  a  few 
years. 

(5)  The  original  soils  at  Cortena  contain  much  saline  and  alkaline 
matter  down  to  a  depth  of  at  least  twelve  feet.  There  is  great 
variability  in  the  distribution  of  this  soluble  matter  throughout  the 
soil,  in  places  very  near  to  each  other. 

(6)  Those  soils  which  have  been  flooded  for  three  or  four  years 
have  lost  most  of  the  alkali  of  the  upper  two  feet,  though  there  is  still 
a  considerable  amount  in  some  places.  Below  three  feet,  there  is  little 
evidence  of  change. 

(7)  The  results  of  this  year's  work  do  not  indicate  that  the  flood- 
ing has  caused  any  great  change  in  the  amount  or  location  of  the  salts 
in  the  soil  at  Cortena,  except  that  chlorides  near  the  surface  have  gone 
down  one  or  two  feet  lower.    No  change  could  be  noted  below  four  feet. 


Bulletin  375]  rice  EXPERIMENTS  21 

(8)  On  the  porous  soils  of  Imperial  Valley,  rice  flooding  in  one 
season  has  greatly  diminished  the  alkali  and  salts  in  the  upper  four 
feet. 

(9)  When  alkali  soils  are  flooded,  the  chlorides  are  most  rapidly 
removed.  Sulfates  may  require  two  or  three  times  as  long  as  chlorides, 
and  carbonates  ten  or  twenty  times  as  long. 

CHANGES  IN  BACTEEIAL  FLORA  OF  RICE  SOILS* 

This  report  is  concerned  with  changes  in  the  soil  bacteria  and  fungi 
produced  by  the  conditions  of  rice  culture. 

For  this  work,  special  soil  samples  were  taken  in  November,  1922, 
shortly  after  the  rice  was  harvested.  These  samples  were  taken  from 
a  rice  plot  and  from  a  fallow  field  nearby  which  had  not  been  flooded 
in  1922.  In  both  cases,  the  soil  samples  considered  represented  depths 
from  0  to  8  inches  and  from  8  to  16  inches. 

The  studies  of  bacteria  have  been  conducted  by  A.  R.  Davis  of  the 
Division  of  Plant  Nutrition,  with  assistance  from  others.  In  detail, 
the  results  are  as  follows: 

(1)  The  total  number  of  organisms  in  the  surface  soil  of  a  rice 
plot  is  about  one-fourth  the  number  in  the  fallow  soil.  The  subsoil 
of  the  rice  plot  has  about  half  as  many  as  the  subsoil  of  the  fallow 
field. 

(2)  Comparison  of  different  forms  in  fallow  and  rice  soils: 

(a)  The  cellulose  destroying  organisms  seem  to  be  slightly,  but  not 
significantly,  more  effective  in  the  fallow  soil. 

(6)  Denitrifying  organisms  are  practically  the  same  in  both  the 
rice  and  the  fallow  soils. 

(c)  Ammonifying  power  is  good  in  both  fallow  and  rice  soil, 
perhaps  a  little  stronger  in  the  former. 

(d)  Nitrogen  fixation  is  much  superior  in  the  surface  of  the  fallow 
soils,  but  in  the  subsoil  there  is  little  difference  between  the  rice  soil 
and  the  fallow  soil. 

(e)  Nitrification  of  ammonium  salts  is  practically  the  same  in  the 
fallow  and  in  the  rice  soils. 

Since  the  number  of  samples  of  soil  that  were  examined  was 
small — twelve  of  the  rice  soil  and  twelve  of  the  fallow  soil — and  since 
only  one  set  of  samples  was  studied,  it  sems  unwise  to  draw  sweeping 
conclusions  from  this  one  season 's  work.    The  validity  of  the  results  is 

*  This  report  also  has  been  prepared  by  P.  L.  Hibbard. 


22-  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

not  questioned,  but  too  little  work  has  been  done  and  too  few  samples 
examined  to  warrant  any  positive  statements.  With  these  reservations, 
the  following  conclusions  are  drawn: 

Summary  regarding  bacterial  flora. — In  most  respects,  there  seems 
to  be  no  very  great  difference  between  the  fallow  and  the  rice  soils  as 
regards  micro-organisms.  Though  some  kinds  of  bacteria  are  less 
active  in  the  soil  which  has  been  flooded,  it  appears  very  probable  that 
this  soil  will  soon  produce  successfully  again  ordinary  grain  crops. 
The  rice  soil  is  most  likely  deficient  in  nitrates,  so  that  some  months, 
perhaps  years,  must  elapse  before  the  soil  is  again  well  supplied 
through  the  usual  soil  building  agencies.  On  the  whole,  there  is  little 
in  this  study  to  indicate  that  the  soil  has  been  permanently  injured 
by  rice  culture. 


II.  PROGRESS  IN  EXPERIMENTS  ON  WATER-GRASS 

CONTROL  AT  THE  BIGGS  RICE  FIELD 

STATION,  1922-23 

By  JENKIN  W.  JONES 
Agronomist,  Cereal  Investigations,  U.  S.  Department  of  Agriculture 


SCOPE  AND  METHOD  OF  EXPERIMENTS 

Expermients  in  water-grass  control  were  first  conducted  at  the 
Biggs  Rice  Field  Station,  Biggs,  California,  in  1916.  Cultivation  was 
given  after  spring  and  summer  irrigation  to  germinate  the  grass  seed. 

These  experiments  showed  that  water  grass  could  be  controlled  to 
a  marked  extent  by  fallowing  the  land  and  giving  it  a  spring  plowing 
after  spring  irrigation,  followed  by  summer  plowing  after  summer 
irrigation.  But  this  method  of  control  involved  considerable  labor  and 
expense,  so  it  never  became  a  general  practice  on  commercial  fields. 
When  foul  land  was  fallowed,  however,  it  usually  was  spring  irrigated 
to  germinate  as  much  grass  seed  as  possible  before  being  plowed. 

Experiments  to  control  water  grass  by  early  submergence  were 
started  on  the  Biggs  Station  in  1921.  The  results  obtained  in  that 
year  were  reported  in  U.  S.  Department  of  Agriculture  Bulletin 
No.  1155. 

More  extensive  experiments  in  water-grass  control,  different  seed- 
ing practices,  and  different  methods  of  irrigation  were  conducted  at 
the  Biggs  Rice  Field  Station  during  the  crop  years  1922  and  1923. 
The  present  paper  is  a  progress  report  on  the  results  of  these 
experiments. 

The  term  water  grass  when  used  in  this  report  includes  all  forms 
of  barnyard  grass  (Echinochloa  crus-galli  and  varieties),  except  the 
white  or  "Japanese"  water  grass. 

The  work  reported  covers  (1)  experiments  on  immediate  sub- 
mergence after  seeding,  including  the  effect  of  sowing  broadcast  on 
the  soil  and  in  the  water  and  the  effect  of  drilling  seed;  (2)  experi- 
ments on  submergence  after  the  rice  has  emerged,  including  com- 
parison of  broadcasting  and  drilling  seed,  and  comparison  of  spring- 
plowing  and  disking  stubble ;  ( 3 )  experiments  on  rate  of  seeding  and 
method  of  irrigation;  (4)  experiments  on  seedbed  preparation,  includ- 


24  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

ing  comparison  of  the  effects  of  good  preparation  and  no  preparation, 
and  the  control  of  cat-tail  by  heavy  seeding;  and  (5)  experiments  on 
rate-of -seeding  with  three  varieties  of  rice.  In  most  of  these  experi- 
ments the  dates  of  seeding  and  depths  of  submergence  also  were  varied. 

During  the  crop  year  1922  the  temperature  was  favorable  for  rice 
production,  but  during  the  crop  year  1923  the  temperature  was  too 
cool  for  maximum  yields  of  rice. 

These  experiments  are  being  conducted  to  determine,  if  possible,  the 
best  method  of  seedbed  preparation,  date  and  rate  of  seeding,  and  date 
and  depth  of  submergence,  for  rice  grown  by  continuous  submergence 
after  broadcast  seeding  or  when  submerged  soon  after  the  rice 
emerges.  They  were  designed  also  to  study  the  effect  of  the  different 
irrigation  methods  on  the  control  of  water  grass  and  on  yields  of  rice. 
The  experiments  have  not  been  conducted  long  enough  to  warrant 
definite  conclusions.  However,  the  results  obtained  during  the  crop 
years  1922  and  1923  should  be  of  interest  to  rice  growers  in  California. 

None  of  the  rice  sown  broadcast  was  harrowed  after  sowing.  On 
plots  submerged  at  specified  depths  the  water  was  maintained  at  as 
near  the  depths  stated  as  was  possible  under  field  conditions,  until 
the  land  was  drained  for  harvest.  All  plots  were  sown  at  the  rate 
of  150  pounds  per  acre  unless  otherwise  stated.  The  few  white  water 
grass  plants  which  appeared  were  pulled  in  all  experiments  except 
No.  4. 


EXPEEIMENTS  ON  IMMEDIATE  SUBMERGENCE  AFTER  SEEDING 

These  experiments  were  conducted  in  1922  and  1923,  on  land  that 
had  been  continuously  cropped  to  rice,  in  the  fertilizer  experiments, 
from  1913  to  1920,  inclusive.  In  1921  the  land  was  fallowed.  The 
1922  crop,  therefore,  was  the  ninth  rice  crop  in  ten  years  and  the  1923 
crop  the  tenth  rice  crop  on  this  land  in  eleven  years.  In  the  spring 
of  1922  the  fallow  land  was  double-disked,  harrowed,  and  dragged. 
For  the  1923  crop  the  land  was  spring  plowed,  harrowed,  and  dragged. 
In  both  years  these  tillage  operations  prepared  a  good  seedbed. 

In  table  1  are  shown  the  annual  and  average  acre  yields  obtained 
from  broadcasted  seed  sown  on  different  dates,  and  immediately  sub- 
merged to  different  depths  in  the  years  1922  and  1923. 

The  yields  given  are  the  average  of  two  tenth-acre  plots  in  each 
case  except  the  check  plots,  where  they  represent  the  averages  from 
four  tenth-acre  plots. 


Bulletin  375] 


RICE   EXPERIMENTS 


25 


TABLE  1 

Annual  and  Average  Acre  Yields  of  Caloro  Kice  on  Plots  Submerged 
Immediately  after  Broadcast  Seeding  in  Date-of-Seeding  and  Depth-of- 
Submergence  Experiments  at  the  Biggs  Eice  Field  Station,  Biggs,  Cali- 
fornia, during  the  Years  1922  and  1923. 


o  Submerged  on  April  28  in  1922. 

6  Yields  slightly  increased  by  an  old  fill. 

c  Affected  by  seepage. 


Seeding 

Submergence 

Acre  yield  in  pounds 

Compared  with 
check 

Date 

Method 

Date 

Depth, 
inches 

1922 

1923 

Average 

Gain 

Loss 

April  25 

Broadcast  on  soil 

April  25° 

4 

3295 

2365 

2830 

419 

April  25 

Broadcast  on  soil 

April  25° 

6 

35206 

3265& 

3392 

981 

April  25 

Broadcast  on  soil 

April  25* 

8 

3265 

2115 

2690 

279 

May    5 

Broadcast  on  soil 

May    5 

4 

2605 

2530 

2667 

156 

May    5 

Broadcast  on  soil 

May    5 

6 

3290 

2655 

2972 

561 

May    5 

Broadcast  on  soil 

May    5 

8 

3075 

2620 

2847 

436 

May  15 

Broadcast  on  soil 

May  15 

2 

2850 

2090 

2470 

59 

May  15 

Broadcast  on  soil 

May  15 

4 

3695 

2075 

2885 

474 

May  15 

Broadcast  on  soil 

May  15 

6 

4250 

2380 

3315 

904 

May  15 

Broadcast  on  soil 

May  15 

8 

3645 

1925 

2785 

374 

May  16 

Broadcast  in  water 

May  15 

4 

3700 

2190 

2945 

534 

May  16 

Broadcast  in  water 

May  15 

6 

2805 

1625 

2215 

196 

May  16 

Broadcast  in  water 

May  15 

8 

4010 

2130 

3070 

659 

May  25 

Broadcast  on  soil 

May  25 

4 

3515 

1560c 

2537 

126 

May  25 

Broadcast  on  soil 

May  25 

6 

2785 

1400c 

2092 

319 

May  25 

Broadcast  on  soil 

May  25 

8 

3110 

1460c 

2285 

126 

April  25 

Drilled 

April  25a 

6 

1740 

2392 

2066 

345 

April  25 

(Check)  Drilled 

June  15 

6 

3250 

1572 

2411 

Check 

EFFECT  OF  SOWING  BROADCAST  ON  THE  SOIL 

In  these  experiments  the  rice  was  sown  broadcast  on  the  soil  and 
the  plots  immediately  submerged  to  the  required  depths.  On  plots 
submerged  two  inches  considerable  water  grass  emerged  in  1923.  On 
plots  submerged  four  inches  some  water  grass  emerged,  but  plots  sub- 
merged six  and  eight  inches  were  practically  free  from  water  grass 
and  sprangle-top  (Leptochloa  fascicularis)  in  both  years.  However, 
other  water  weeds  appear  to  grow  equally  well  at  all  depths  of  sub- 
mergence. The  same  effect  on  water  grass  was  noted  for  all  dates  of 
seeding.  However,  seepage  on  some  plots  started  growth  of  water  grass 
before  the  rice  was  sown  and  the  plots  submerged  and  these  plots  had 
more  grass  and  poorer  stands  than  those  not  effected  by  seepage. 


26  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION 


EFFECT  OF  SOWING  BROADCAST  IN  THE  WATER 

In  this  experiment  the  plots  were  submerged  to  the  required  depths 
and  the  rice  was  then  sown  broadcast  in  the  water.  The  effect  on 
water-grass  control  was  the  same  in  this  experiment  as  when  the  rice 
was  sown  broadcast  on  the  soil  and  the  land  immediately  submerged. 
However,  less  seed  usually  is  required  to  obtain  good  stands  when  rice 
is  sown  broadcast  in  the  water  than  when  it  is  sown  broadcast  on  soil 
and  then  submerged. 

EFFECT  OF  DRILLING  SEED 

On  these  plots  the  rice  was  drilled  about  one  to  one  and  one-half 
inches  deep  and  immediately  submerged  to  a  depth  of  six  inches.  The 
water  grass  was  effectively  controlled,  but  poor  stands  and  low  yields 
of  rice  were  obtained.  The  poor  stands  permitted  the  growth  of  red- 
stem  (Ammania  coccinea),  annual  sedge  (Cyperus  difformis),  and 
cat-tail  (Typha  latifolia),  and  when  these  weeds  are  abundant  they 
reduce  the  yields  of  rice. 

EFFECT  OF  IRRIGATING  DRILLED  CHECK  PLOTS  IN  THE  ORDINARY  WAY 

The  check  plots  were  drilled  and  then  irrigated  and  drained  when 
necessary  until  thirty  days  after  the  rice  emerged.  They  were  then 
submerged  six  inches.  These  plots  were  rather  foul  with  water  grass 
and  sprangle-top  in  both  years,  which  no  doubt  reduced  the  acre  yields. 

conclusions 

The  results  of  these  experiments  as  shown  in  table  1  indicate  that 
the  following  conclusions  are  justified : 

(1)  Rice  should  be  sown  broadcast  comparatively  early  and 
immediately  submerged  to  a  depth  of  about  six  inches;  (2)  there  is  a 
slight  advantage  in  yield,  and  a  marked  decrease  in  acre  cost  when 
rice  is  sown  broadcast  and  immediately  submerged,  compared  with  rice 
sown  broadcast  in  the  water;  (3)  rice  seed  should  not  be  drilled  if 
the  land  is  to  be  submerged  immediately  after  seeding,  because  con- 
siderable seed  rots  if  covered  with  both  soil  and  water  and  this  results 
in  poor  stands  and  usually  in  low  yields;  (4)  rice  sown  broadcast  and 
immediately  submerged  four,  six  or  eight  inches,  or  rice  sown  in  the 
water  for  all  dates  of  seeding  except  May  25,  gave  higher  average 
yields,  with  one  exception,  than  did  the  check  plots. 


Bulletin  375]  RICe  EXPERIMENTS  27 


COMPARISON  OF  AIR  AND  WATER  TEMPERATURES 

Rice  is  commonly  sown  in  California  between  April  15  and  May  15. 
At  this  time  the  temperatures  of  the  air,  water,  and  soil  usually  are 
too  low  for  maximum  germination.  During  the  growing  season  of 
1923,  a  soil  thermograph  was  used  to  get  temperature  records  on  a 
plot  sown  broadcast  and  submerged  six  inches  on  April  25.  The  soil 
thermograph  ' '  torpedo ' '  was  placed  horizontally  on  the  surface  of  the 
soil  beneath  the  six  inches  of  water.  The  maximum  and  minimum  air 
temperatures  were  taken  daily  under  shade  but  with  a  free  circulation 
of  air.    Records  were  taken  from  May  to  September,  inclusive. 

The  average  maximum  temperature  for  the  five-month  period  from 
May  to  September,  inclusive  was  87.8°  F.  for  the  air  and  79.6°  F.  for 
the  water.  The  average  minimum  temperature  for  the  same  five-month 
period  was  56.4°  F.  for  the  air  and  60.6°  F.  for  the  water. 

The  average  maximum  air  and  water  temperatures  for  the  months 
of  May  and  June,  during  which  time  the  rice  was  germinating  and 
before  it  was  large  enough  to  shade  the  water  effectively,  were,  for 
May,  air  80.1°  and  water  82.7°,  and  in  June,  air  83.5°  and  water  85°  F. 
The  average  minimum  temperatures  for  the  same  months  were  for 
May,  air  50.9°  and  water  53.7°,  and  for  June,  air  54°  and  water  58.6°  F. 

During  July,  August,  and  September,  the  water  was  almost  com- 
pletely shaded  by  the  rice  crop,  and  the  average  maximum  air  tem- 
perature for  each  month  ranged  from  9°  to  18.7°  F.  higher  than  the 
average  maximum  water  temperature.  However,  the  average  mini- 
mum water  temperature  for  each  month  ranged  from  1.5°  to  6.7°  F. 
higher  than  the  average  minimum  air  temperature. 

The  temperature  readings  in  1923  indicate  that  water  to  a  depth 
of  six  inches  maintains  a  higher  and  more  uniform  temperature  than 
the  air  during  the  period  of  germination  and  early  growth.  For  May 
the  mean  water  temperature  was  5.4°  higher  than  that  of  the  air,  and 
for  June  it  was  6.1°  higher.  This  indicates  that,  in  so  far  as  tempera- 
ture alone  is  concerned,  conditions  are  more  favorable  for  germination 
under  six  inches  of  water  than  they  are  in  the  atmosphere,  or  than 
they  are  presumably  at  the  surface  of  the  soil. 


28  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

EXPEEIMENTS  ON  SUBMERGENCE  AFTER  THE  RICE  HAS  EMERGED 
BROADCASTING  AND  DRILLING  SEED   COMPARED 

These  experiments  were  conducted  in  1922  and  1923  on  land  that 
had  been  sown  to  rice  and  fallowed  in  the  cultural  experiments  in 
alternate  years  from  1914  to  1921.  In  1921  the  land  was  fallowed. 
The  1922  crop  was  the  fifth  rice  crop  on  this  land  in  ten  years.  In 
the  spring  of  1922  the  land  was  double-disked  and  harrowed.  For  the 
1923  crop  the  land  was  spring  plowed,  double-disked,  dragged,  and 
harrowed.  In  both  years  these  tillage  operations  prepared  a  good 
seedbed. 

The  annual  and  average  acre  yields  from  plots  both  broadcast  and 
drilled,  sown  on  two  different  dates  and  submerged  at  various  depths 
after  the  rice  emerged  in  the  years  1922  and  1923,  are  shown  in  table  2. 
The  annual  yields  of  all  except  the  check  plots  represent  the  average 
yields  of  two  tenth-acre  plots.  The  annual  yields  of  the  broadcast 
checks  are  for  two  plots  irrigated  by  the  ordinary  method.  The  annual 
yields  of  the  drilled  check  plots  are  the  averages  of  four  plots  in  all 
cases,  except  the  yield  recorded  for  May  5  seeding  in  1923,  which  is 
for  only  two  plots. 

In  these  experiments  alternate  plots,  usually  inclosed  by  the  same 
levees,  were  sown  broadcast  and  drilled,  respectively.  In  both  years 
the  rice  was  irrigated  and  the  plots  drained  three  times  before  the 
plots  finally  were  submerged  to  the  required  depths.  On  the  date  of 
submergence  the  rice  and  water  grass  varied  in  height  from  one  to 
two  inches.  In  each  year  better  stands  and  higher  yields  were 
obtained  on  plots  sown  on  April  25  than  from  those  sown  on  May  5. 

The  plots  submerged  two  and  four  inches  were  foul  with  water 
grass  and  sprangle-top  in  both  years.  On  plots  submerged  six  and 
eight  inches  deep  the  water  grass  was  controlled  to  a  marked  extent, 
but  at  such  depths  a  good  deal  of  rice  was  suffocated  each  season. 
There  was  some  water  grass  and  sprangle-top  present  on  all  plots  in 
both  years,  but  these  grasses  were  much  more  abundant  on  the  check 
plots  and  those  submerged  two  and  four  inches  than  on  the  plots 
submerged  six  and  eight  inches.  Submergence  immediately  after  the 
rice  was  sown  broadcast  (table  1)  was  much  more  effective  in  the 
control  of  water  grass  than  early  submergence  of  drilled  or  broadcast 
rice  after  it  had  emerged. 

*  The  results  of  these  experiments,  as  shown  in  table  2,  indicate  that 
(1)  early  seeding  is  better  than  late  seeding;  (2)  two-inch  and  four- 
inch  submergence  results  in  higher  yields  than  six-inch  and  eight-inch 


Bulletin  375] 


RICE   EXPERIMENTS 


29 


submergence,  due  largely  to  the  fact  that  much  rice  is  suffocated  by 
the  water  when  submerged  six  and  eight  inches  after  it  has  emerged ; 
(3)  there  is  not  a  very  marked  difference  in  yields  of  drilled  and 
broadcast  plots,  but  yields  from  the  drilled  plots  were  slightly  higher ; 
and  (4)  this  method  of  irrigation  by  deferred  submergence  of  either 

TABLE  2 

Annual  and  Average  Acre  Yields  of  Caloro  Kice  Obtained  on  Plots  Sown  on 
Two  Different  Dates,  Both  Broadcast  and  Drilled,  and  Submerged  at 
Various  Depths  after  the  Eice  Emerged,  at  the  Biggs  Eice  Field  Station, 
Biggs,  California,  in  the  Years  1922  and  1923. 


Seeding 

Submergence 

Annual  and  average  acre 
yields  in  pounds 

Compared  with 
check 

Date 

Method 

Date 

Depth, 
inches 

1922 

1923 

Average 

Gain, 
pounds 

Loss, 
pounds 

April  25 

Broadcast 

May  29a 

2 

2280 

1830 

2055 

62 

April  25 

Drilled 

May  29a 

2 

2690 

2110 

2400 

173 

April  25 

Broadcast 

May  29a 

4 

2580 

2240 

2410 

293 

April  25 

Drilled 

May  29a 

4 

2450 

1985 

2217 

10 

April  25 

Broadcast 

May  29° 

6 

2060 

2095 

2077 

40 

April  25 

Drilled 

May  29a 

6 

2480 

1815 

2147 

80 

April  25 

Broadcast 

May  29° 

8 

2300 

1520 

1910 

207 

April  25 

Drilled 

May  29a 

8 

2270 

2145 

2207 

20 

April  25 

Broadcast 

June  15 

6 

2590 

1645 

2117 

April  25 

Drilled 

June  15 

6 

2450 

2004 

2227 

May    5 

Broadcast 

June    86 

4 

2050 

1220 

1635 

425 

May    5 

Drilled 

June    86 

4 

2060 

1675 

1867 

177 

May    5 

Broadcast 

June    86 

6 

1995 

1210 

1602 

392 

May    5 

Drilled 

June    8& 

6 

2085 

1320 

1702 

12 

May    5 

Broadcast 

June    Sb 

8 

1825 

905 

1365 

155 

May    5 

Drilled 

June    8& 

8 

1735 

825 

1280 

410 

May    5 

Broadcast 

June  25 

6 

1210 

1210 

May    5 

Drilled 

June  25 

6 

1875 

1505 

1690 

a  Submerged  on  May  24  in  1923. 
&  Submerged  on  June  4  in  1923. 


broadcast  or  drilled  rice  is  inferior  to  continuous  submergence 
immediately  after  the  rice  is  sown  broadcast,  both  in  regard  to  water- 
grass  control  and  to  rice  yields. 

The  rice  plant  apparently  is  unable  to  adjust  itself  to  the  sudden 
change  from  a  dry  or  moist  soil  to  a  submerged  life.  Many  of  the 
young  plants  are  suffocated  in  deep  water  (six  and  eight  inches)  and 
those  which  emerge  are  slow  in  regaining,  if  they  ever  fully  regain, 
their  normal  vitality.    However,  when  the  rice  seed  germinates  under 


30  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

water  and  the  seedlings  emerge  through  the  water,  such  plants  appear 
to  be  more  vigorous  than  plants  grown  by  the  ordinary  method  of 
irrigation. 

SPRING  PLOWING  AND  DISKING  OF  STUBBLE  COMPARED 

These  experiments  were  conducted  on  land  which  had  been 
alternately  cropped  to  rice  and  fallowed  in  the  cultural  experiments 
from  1914  to  1921.  The  land  produced  a  rice  crop  in  1921.  The  crop 
of  1922  was  the  sixth  rice  crop  on  this  land  in  ten  years. 

In  the  springs  of  1922  and  1923,  one  series  of  plots  was  double- 
disked  and  harrowed.  A  second  series  of  plots  was  spring  plowed, 
double-disked  and  dragged.  These  tillage  operations  prepared  a  good 
seedbed  on  the  spring-plowed  land,  but  a  poor,  hard,  grassy  seedbed 
on  the  disked  stubble  land. 

The  annual  and  average  acre  yields  for  these  method-of -seeding 
experiments  on  spring  plowed  and  on  disked  stubble  land,  submerged 
at  various  depths  after  the  rice  emerged  in  the  years  1922  and  1923, 
are  shown  in  table  3. 

Each  of  the  four  check  plots  was  a  single  tenth-acre  plot  each  year, 
and  irrigated  in  the  ordinary  way.  The  sizes  and  numbers  of  all  the 
plots,  except  the  check  plots,  are  shown  in  footnotes  to  table  3. 

In  these  experiments  alternate  plots,  usually  inclosed  in  the  same 
levees,  were  broadcast  and  drilled.  In  both  years  the  rice  was  irrigated 
and  drained  three  times  before  the  plots  were  submerged  to  the 
required  depths.  On  the  date  of  submergence  the  rice  and  water  grass 
varied  in  height  from  one  to  two  inches. 

Each  year  the  plots  submerged  two  and  four  inches  were  quite  foul 
with  water  grass  and  sprangle-top.  On  plots  submerged  six  and  eight 
inches  the  water  grass  was  controlled  to  a  certain  extent,  but  in  both 
seasons  much  rice  was  suffocated  when  submerged  at  these  depths. 
While  the  plots  submerged  six  and  eight  inches  had  much  less  water 
grass  than  plots  submerged  two  and  four  inches,  the  stands  of  rice  in 
the  deeply  submerged  plots  were  too  thin  to  make  good  yields.  The 
stands  on  deep-water  plots  also  were  reduced  in  1922  by  injury  from 
leaf  miners  and  by  the  growth  of  spike-rush. 

Spike-rush  (Eleocharis  palustris),  locally  known  as  wire  grass, 
cat-tail  (Typha  latifolia),  slender  aster  (Aster  exilis),  annual  sedge 
(Cy penis  difformis) ,  and  canary  grass  (Phalaris)  were  quite  thick  in 
both  years  on  the  disked  stubble  land.  On  the  spring-plowed  land 
very  few  of  these  weeds  except  the  annual  sedge  were  present. 


Bulletin  375] 


RICE   EXPERIMENTS 


31 


The  results  of  these  experiments  as  shown  in  table  3  indicate  that 
(1)  shallow  submergence  is  better  than  deep  submergence  with  this 
method  of  irrigation,  (2)  this  method  of  irrigation  is  inferior  to 
continuous   submergence    immediately    after    broadcasting,    both    in 


TABLE  3 

Annual  and  Average  Acre  Yields  of  Caloro  Eice  Obtained  on  Spring-plowed 
and  on  Double-disked  Stubble  Land  in  Plots  either  Broadcasted  or 
Drilled,  and  Submerged  at  Various  Depths  after  the  Eice  Emerged,  at 
the  Biggs  Eice  Field  Station,  Biggs,  California,  during  the  Crop  Years 
1922  and  1923. 


Annual  and  average  acre 

Compared  with 

Seed-bed 
preparation 

Method  of 
seeding 

Submergence 

yields  in  pounds 

check 

Date 

Depth 

1922 

1923 

Average 

Gain 

Loss 

Spring  Plowed 

Drilled 

May  30 

2 

3510- 

2115" 

2812 

492 

Double  Disked 

Drilled 

May  30 

2 

2430" 

1395" 

1912 

17 

Spring  Plowed 

Broadcast 

May  30 

4 

2585c 

2235c 

2410 

590 

Double  Disked 

Broadcast 

May  30 

4 

2180c 

1335c 

1757 

422 

Spring  Plowed 

Drilled 

May  30 

4 

2460c 

2605c 

2532 

212 

Double  Disked 

Drilled 

May  30 

4 

2455c 

1510c 

1982 

87 

Spring  Plowed 

Broadcast 

May  30 

6 

2317d 

2037d 

2177 

357 

Double  Disked 

Broadcast 

May  30 

6 

1803d 

1177d 

1490 

155 

Spring  Plowed 

Drilled 

May  30 

6 

2248e 

2042* 

2145 

175 

Double  Disked 

Drilled 

May  30 

6 

2048e 

1383d 

1715 

180 

Spring  Plowed 

Broadcast 

May  30 

8 

1360d 

1640d 

1500 

320 

Double  Disked 

Broadcast 

May  30 

8 

1037d 

980c 

1008 

327 

Spring  Plowed 

Drilled 

May  30 

8 

1540c 

1950c 

1745 

575 

Double  Disked 

Drilled 

May  30 

8 

1405c 

710c 

1057 

838 

Spring  Plowed 

Broadcast 

June  16 

6 

1760& 

1880& 

1820 

Double  Disked 

Broadcast 

June  16 

6 

1780b 

8906 

1335 

Spring  Plowed 

Drilled 

June  16 

6 

2220b 

24206 

2320 

Double  Disked 

Drilled 

June  16 

6 

2590b 

1200* 

1895 

o  Single  fifteenth-acre  plots. 

&  Single  tenth-acre  plots. 

e  Average  of  four  tenth-acre  plots. 


c  Average  of  two  tenth-acre  plots. 
d  Average  of  three  tenth-acre  plots. 


control  of  grass 'and  in  rice  yields,  and  (3)  rice  stubble  should  be 
plowed  to  help  control  such  weeds  as  cat-tail,  spike-rush,  canary  grass, 
slender  aster,  and  perennial  sedges. 

The  two-year  average  acre  yield  of  all  plots  on  spring-plowed  land 
was  590  pounds  higher  than  that  of  plots  on  the  disked  stubble  land. 
This  increase  in  yield  indicates  the  necessity  and  value  of  plowing 
stubble  land. 


32 


UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION 


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Bulletin  375]  rice  EXPERIMENTS  33 


EXPERIMENTS  ON  BATE  OF  SEEDING  AND  METHOD  OF  IRRIGATION 

These  experiments  were  conducted  on  land  previously  used  in  the 
irrigation  experiments.  The  land  was  fallowed  in  1921.  The  1922 
crop  was  the  sixth  rice  crop  on  this  land  in  nine  years.  In  the  spring 
of  1922  the  land  was  double-disked  twice,  harrowed,  and  dragged. 
For  the  1923  crop  the  land  was  spring  plowed,  double-disked,  har- 
rowed, and  dragged.  These  tillage  operations  prepared  a  good  seed- 
bed each  year.  The  annual  and  average  acre  yields  for  these  rate-of- 
seeding  and  method-of -irrigation  experiments  in  the  years  1922  and 
1923,  are  shown  in  table  4. 

On  series  1  in  table  4  the  rice  was  sown  broadcast  and  the  plots 
immediately  submerged  six  inches.  On  series  2  the  rice  was  drilled 
and  irrigated  and  drained  twice  before  the  rice  emerged.  It  was  then 
submerged  six  inches.  On  series  3  the  rice  was  drilled  and  then 
irrigated  and  drained  several  times,  and  then  was  submerged  six 
inches,  thirty  days  after  the  rice  emerged. 

The  plots  on  which  the  rice  was  sown  broadcast  and  immediately 
submerged  (series  1)  were  practically  free  from  water  grass  and 
sprangle-top  in  both  years.  The  annual  sedge  was  quite  thick  each 
year,  due  to  thin  stands  of  rice.  Plots  on  which  the  rice  was  drilled 
and  irrigated  and  drained  twice  before  submergence  (series  2)  had 
considerable  water  grass  and  sprangle-top  present  in  both  seasons. 
The  plots  irrigated  in  the  old  way  (series  3)  were  quite  foul  in  1922 
and  very  foul  in  1923. 

The  highest  average  acre  yield  on  series  1  was  obtained  from  the 
190-pound  rate  of  seeding  and  on  series  2  and  series  3  from  the  130- 
pound  of  rate  of  seeding.  The  average  acre  yield  of  all  plots  on 
series  1  and  on  series  2  was  higher  than  that  for  the  plots  on  series  3 
in  both  years. 


EXPERIMENTS  ON  SEEDBED  PREPARATION 

The  land  on  which  these  experiments  were  conducted  had  grown 
six  rice  crops  in  nine  years  and  was  very  foul.  It  produced  a  crop  in 
1921  by  continuous  submergence.  In  the  springs  of  1922  and  1923 
the  land  was  spring  plowed,  double-disked  and  dragged,  except  for 
two  plots  which  received  no  seedbed  preparation  in  1922. 

The  rice  either  was  sown  broadcast  and  immediately  submerged 
to  the  required  depths,  or  the  land  was  submerged  and  the  rice  then 


34 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


sown  broadcast  in  the  water.  The  annual  and  average  acre  yields 
from  these  seed-bed-preparation  experiments  in  the  years  1922  and 
1923  are  shown  in  table  5. 

TABLE  5 

Annual  and  Average  Acre  Yields  of  Caloro  Eice  Obtained  by  Broadcast 
Seeding  on  Well-prepared  and  Unprepared  Seedbeds,  with  Different 
Depths  of  Submergence,  at  the  Biggs  Eice  Field  Station,  Biggs,  Cali- 
fornia, in  the  Years  1922  and  1923. 


Seed- 
bed 
Prepa- 
ration 

Seeding 

Date  of 
Submer- 
gence 

Depth  of 
Submer- 
gence, 
inches 

Annual  and  average  acre 
yields  in  pounds 

Date 

Method 

1922 

1923 

Average 

Good 
Good 
Good 
Good 
Good 
None 
None 

May    9 
May    9 
May  15c 
May    9 

May    9 
May    9 

May  15 

Broadcast 

Broadcast 

Broadcast  in  water 

Broadcast 

Broadcast 

Broadcast 

Broadcast  in  water 

May  11 
May  11 
May  11 
May  11 
May  11 
May  11 
May  11 

4 
6 
6 
8 
6 
6 
6 

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35536 
3144d 

35896 
2590/ 
2768* 
2024" 

2148* 
19596 
1941rf 
2661* 
2030/ 

2820 
2756 
2542 
3125 
2310 

o  Yields  of  single  half-acre  plots. 

&  Average  yields  of  two  half-acre  plots. 

o  Sown  on  May  14  in  1923. 

d  Yields  of  single  plot. 

e  Average  yields  of  three  half-acre  plots. 

f  Average  yield  of  two  third-acre  plots  sown  at  rate  of  200  lbs.  per  acre. 

9  Yield  of  single  fourth-acre  plots. 


EFFECT  OF  GOOD  PREPARATION 

On  prepared  seedbeds  there  was  very  little  water  grass  on  plots 
submerged  four,  six,  and  eight  inches,  except  for  the  white  or 
"Japanese"  water  grass,  which  was  present  to  a  considerable  extent 
on  all  plots  in  1921  and  1922,  and  was  sufficiently  thick  in  1923  to 
materially  reduce  rice  yields.  The  results  indicate  that  white  water 
grass  cannot  be  controlled  by  continuous  submergence  to  these  depths. 
Observations  along  "barrow  pits"  at  the  base  of  the  levees,  and  in 
dead  furrows,  indicate  that  water  ranging  from  ten  to  fifteen  inches 
deep  does  aid  materially  in  controlling  white  water  grass.  At  such 
depths,  however,  it  is  difficult  to  get  good  stands  of  rice  and  also  it  is 
impracticable  to  hold  the  water  so  deep.  It  appears,  therefore,  that 
white  water  grass  when  thin  should  be  pulled  to  prevent  spreading. 


Bulletin  375]  RICe  EXPERIMENTS  35 


EFFECT  OF  NO  PREPARATION 

The  plots  sown  in  1922  on  stubble  land  without  seedbed  prepa- 
ration were  quite  foul  with  spike-rush,  cat-tail,  slender  aster,  and 
canary  grass.  Water  grass  also  was  much  thicker  on  these  than  on 
plots  which  were  spring  plowed.  Some  water  grass  usually  germinates 
in  the  spring  before  the  land  is  prepared  for  seeding  and  such  plants 
must  be  killed  by  cultivation  as  it  is  practically  impossible  to  control 
or  suffocate  them  with  water  six  to  eight  inches  deep. 

CONTROL  OF   CAT-TAIL  BY   HEAVY  SEEDING 

Seeding  at  the  rate  of  200  pounds  per  acre  on  land  badly  fouled 
with  cat-tail  did  not  check  the  growth  of  the  cat-tail.  However,  it  has 
been  observed  during  past  years  that  on  clean  land  good  stands  of  rice 
are  very  helpful  in  preventing  cat-tail  from  becoming  established. 
Cat-tails  usually  first  appear  in  a  field  where  the  stands  of  rice  are 
poor,  that  is,  along  the  levees  and  on  low  land  where  it  is  difficult  to 
secure  good  stands  of  rice. 

conclusions 

The  results  of  these  experiments  indicate  that  ( 1 )  it  is  not  profitable 
to  grow  rice  on  unprepared  seedbeds  because  of  low  yields,  caused  in 
part,  at  least,  by  competition  with  spike-rush,  cat-tail,  slender  aster, 
canary  grass,  and  water  grass;  (2)  sowing  in  the  water  has  no 
advantage  over  sowing  broadcast  and  immediately  submerging  the 
land,  except  that  less  seed  usually  is  required  to  secure  good  stands 
when  sown  in  the  water,  but  this  saving  in  seed  probably  is  more  than 
offset  by  the  increased  cost  of  seeding  in  water;  and  (3)  eight  inches 
of  water  is  the  best  depth  to  hold  continuously  after  the  rice  is  sown 
broadcast. 


EXPERIMENTS  ON  RATES  OF  SEEDING  WITH  THREE  VARIETIES 

The  rate-of -seeding  experiment  which  was  started  in  1921  included 
three  varieties  of  rice,  Selection  No.  175,  Caloro,-  and  Wataribune, 
C.  I.  No.  1561.  The  land  used  for  this  experiment  was  fallowed  in 
1920.  The  1921  crop  was  grown  on  fallow  land,  and  the  1922  and 
1923  crops  were  grown  on  spring-plowed  stubble  land. 

Each  variety  and  rate  of  seeding  was  located  on  the  same  plot  each 
year.    A  reasonably  good  seedbed  was  prepared  before  seeding.    The 


36 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


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Bulletin  375]  RICE  experiments  37 

rates  of  seeding  for  each  variety  ranged  from  85  to  175  pounds  per 
acre.  The  rice  on  all  plots  was  sown  with  a  drill  on  the  same  date 
each  year. 

After  seeding,  all  plots  were  irrigated  and  drained  at  frequent 
intervals  until  thirty  days  after  the  rice  emerged.  The  land  then  was 
submerged  about  six  inches  and  the  water  held  at  this  depth  until  the 
land  was  drained  for  harvest.  The  water  grass  which  appeared  was 
hand-pulled  before  it  reached  maturity. 

The  annual  and  average  acre  yields,  for  the  rate-of-seeding  experi- 
ment with  Selection  No.  175,  Caloro,  and  Wataribune,  during  the 
three-year  period  from  1921  to  1923,  inclusive,  are  shown  in  table  6. 

Those  who  are  familiar  with  cereal  crops  know  that  the  maximum 
yield  of  a  given  variety  is  not  likely  to  be  obtained  from  the  same 
rate  of  seeding  each  year.  However,  in  a  period  of  years  each  variety 
probably  will  produce  its  maximum  average  yield  at  some  constant 
rate  of  seeding.  It  is  not  possible  to  conduct  a  rate-of-seeding  experi- 
ment for  each  variety,  due  to  the  large  number  of  varieties.  Recom- 
mendations as  to  the  best  rate  of  seeding,  therefore,  usually  are  based 
on  the  results  of  rate-of-seeding  experiments  with  one  or  two  of  the 
leading  commercial  varieties  grown  in  a  given  area, 

The  rate  of  seeding  for  rice  is  influenced  by  many  factors,  some  of 
the  most  important  of  which  are  variety,  age  of  seed,  quality  of  seed, 
date  of  seeding,  depth  of  seeding,  method  of  seeding,  condition  of  the 
seedbed,  method  of  irrigation  and  kind  of  land,  whether  new  or  old, 
rich  or  poor. 

In  table  6  it  will  be  noted  that,  for  Selection  No.  175,  the  average 
acre  yield  increased  with  each  increased  rate  of  seeding  from  85  to 
150  pounds  per  acre.  For  Caloro  the  average  yield  did  not  show 
consistent  increases  for  increased  rates  of  seeding.  However,  the 
highest  average  yields  were  obtained  from  the  175-pound  and  150- 
pound  rates.  The  average  acre  yields  for  Wataribune  show  consistent 
increases  with  increased  rates  of  seeding  from  85  to  150  pounds  per 
acre,  except  for  the  115-pound  rate. 

The  three-year  average  yield,  at  all  rates  of  seeding,  for  Selection 
No.  175  was  2876  pounds,  for  Caloro  2718  pounds,  and  for  Wataribune 
28t)l  pounds  per  acre. 

These  results  indicate  that  on  old  land  rice  probably  should  be 
sown  at  the  rate  of  150  pounds  per  acre. 


38  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 

SUMMARY 

1.  Rice  sown  broadcast  and  immediately  and  continuously  sub- 
merged, or  rice  sown  broadcast  in  the  water  and  kept  submerged 
thereafter,  appears  to  have  three  distinct  advantages  over  rice 
irrigated  in  the  old  way:  (1)  it  matures  from  seven  to  ten  days 
earlier  than  rice  irrigated  in  the  old  wray,  depending  somewhat  upon 
the  date  of  seeding,  for  there  is  less  difference  from  early  than  from 
late  dates  of  seeding;  (2)  continuous  submergence  does  control  the 
most  common  forms  of  water  grass  and  sprangle-top ;  (3)  the  rice 
appears  to  develop  into  better  plants  than  those  grown  by  the  old 
method  of  irrigation. 

2.  When  rice  is  drilled  and  immediately  submerged  it  appears  that 
considerable  seed  rots,  and  this  often  results  in  poor  stands  and  low 
yields  of  rice. 

3.  When  rice  is  drilled  or  broadcast  and  irrigated  lightly  for  two 
to  four  weeks  to  bring  it  up  before  it  is  permanently  submerged, 
shallow  submergence  at  two  and  four  inches  apparently  does  not 
control  the  water  grass.  Deep  submergence  at  six  and  eight  inches 
does  aid  in  control  of  water  grass,  but  such  depths  also  suffocate  so 
much  rice  that  low  yields  are  produced. 

4.  The  results  indicate  that  good  seedbed  preparation  pays.  It 
does  not  pay  to  grow  rice  on  a  seedbed  prepared  merely  by  disking 
stubble  land,  because  such  weeds  as  spike-rush,  slender  aster,  cat-tail, 
canary  grass,  and  perennial  sedge  reduce  the  yields  below  profitable 
limits.  Good  spring  plowing  aids  materially  in  the  control  of  these 
weeds. 

5.  The  results  indicate  that  rice  should  be  sown  at  a  higher  rate 
when  it  is  grown  loy  continuous  submergence  immediately  after 
broadcasting  than  when  it  is  grown  by  the  old  method  of  irrigation. 

6.  The  results  indicate  that  on  land  foul  with  cat-tail  a  heavy  rate 
of  seeding  (200  pounds  per  acre)  does  not  help  to  control  the  cat-tail. 
But  good  stands  of  rice  apparently  do  aid  in  preventing  cat-tail  from 
entering  a  clean  rice  field. 

7.  It  appears  that  less  seed  is  required  to  obtain  good  stands  when 
rice  is  sown  broadcast  in  the  water  than  when  sown  broadcast  on  the 
soil  and  then  submerged.  This  probably  is  due  to  the  fact  that  when 
sown  broadcast  and  then  submerged  considerable  seed  is  covered  by 
slacked  clods  and  rots  before  germination. 

8.  The  results  indicate  that,  on  old  land,  rice  probably  should  be 
sown  at  the  rate  of  150  pounds  per  acre  when  grown  by  the  old  method 
of  irrigation. 


STATION  PUBLICATIONS  AVAILABLE  TOE  FREE  DISTRIBUTION 


No. 

253.  Irrigation  and  Soil  Conditions  in  the 
Sierra  Nevada  Foothills,  California. 

261.  Melaxuma    of    the    Walnut,    "Juglans 

regia." 

262.  Citrus   Diseases   of   Florida    and    Cuba 

Compared  with  those  of  California. 

263.  Size  Grades  for  Ripe  Olives. 

268.   Growing  and  Grafting  Olive  Seedlings. 
273.  Preliminary  Report  on  Kearney  Vine- 
yard Experimental  Drain. 

275.  The  Cultivation  of  Belladonna  in  Cali- 

fornia. 

276.  The   Pomegranate. 

277.  Sudan  Grass. 

278.  Grain   Sorghums. 

279.  Irrigation  of  Rice  in  California. 

280.  Irrigation  of  Alfalfa  in  tHe  Sacramento 

Valley. 
283.  The  Olive  Insects  of  California. 

285.  The  Milk  Goat  in  California. 

286.  Commercial   Fertilizers. 

287.  Vinegar  from  Waste  Fruits. 
294.  Bean  Culture  in  California. 
298.   Seedless  Raisin  Grapes. 

804.  A  Study  of  the  Effects  of  Freezes  on 
Citrus  in   California. 

808.  I.  Fumigation  with  Liquid  Hydrocyanic 
Acid.  II.  Physical  and  Chemical  Prop- 
erties of  Liquid  Hydrocyanic  Acid. 

812.  Mariout  Barley. 

317.  Selections  of  Stocks  in  Citrus  Propa- 
gation. 

319.  Caprifigs  and  Capriflcation. 

321.  Commercial  Production  of  Grape  Syrup. 

324.  Storage  of  Perishable  Fruit  at  Freezing 
Temperatures. 

825.  Rice  Irrigation  Measurements  and  Ex- 
periments in  Sacramento  Valley, 
1914-1919. 

328.   Prune  Growing  in  California. 

331.  Phylloxera-Resistant  Stocks. 

334.  Preliminary  Volume  Tables  for  Second- 

Growth  Redwood. 

335.  Cocoanut   Meal    as   a   Feed   for   Dairy 

Cows  and  Other  Livestock. 

336.  The  Preparation   of  Nicotine  Dust  as 

an  Insecticide. 


BULLETINS 

No. 
339. 


341. 
343. 
344. 

346. 
347. 

348. 
349. 

350. 
351. 
352. 

353. 
354. 
355. 
357. 


358. 

359. 
360. 

361. 

362. 
363. 

364. 

366. 

367. 

368. 

369. 
370. 
371. 


The  Relative  Cost  of  Making  Logs  from 
Small    and    Large   Timber. 

Studies  on  Irrigation  of  Citrus  Groves. 

Cheese  Pests  and  Their  Control. 

Cold  Storage  as  an  Aid  to  the  Market- 
ing of  Plums. 

Almond  Pollination. 

The  Control  of  Red  Spiders  in  Decidu- 
ous Orchards. 

Pruning  Young  Olive  Trees. 

A  Study  of  Sidedraft  and  Tractor 
Hitches. 

Agriculture  in  Cut-over  Redwood  Lands. 

California  State  Dairy  Cow  Competition. 

Further  Experiments  in  Plum  Pollina- 
tion. 

Bovine  Infectious  Abortion. 

Results  of  Rice  Experiments  in   1922. 

The  Peach  Twig  Borer. 

A  Self-mixing  Dusting  Machine  for 
Applying  Dry  Insecticides  and 
Fungicides. 

Black  Measles,  Water  Berries,  and 
Related   Vine   Troubles. 

Fruit  Beverage  Investigations. 

Gum  Diseases  of  Citrus  Trees  in  Cali- 
fornia. 

Preliminary  Yield  Tables  for  Second 
Growth  Redwood. 

Dust  and  the  Tractor  Engine. 

The  Pruning  of  Citrus  Trees  in  Cali- 
fornia. 

Fungicidal  Dusts  for  the  Control  of 
Bunt. 

Turkish  Tobacco  Culture,  Curing  and 
Marketing. 

Methods  of  Harvesting  and  Irrigation 
in  Relation  to  Mouldy  Walnuts. 

Bacterial  Decomposition  of  Olives  dur- 
ing Pickling. 

Comparison  of  Woods  for  Butter  Boxes. 

Browning  of  Yellow  Newtown  Apples. 

The  Relative  Cost  of  Yarding  Small 
and  Large  Timber. 


CIRCULARS 

No.  No. 

70.  Observations   on    the    Status   of    Corn  161. 

Growing  in  California.  164. 

87.  Alfalfa.  165. 

111.  The  Use  of  Lime  and  Gypsum  on  Cali- 
fornia Soils.  166. 

118.  Correspondence  Courses  in  Agriculture.  167. 

117.  The    Selection    and   Cost   of    a    Small  170! 
Pumping  Plant. 

127.  House  Fumigation.  172. 

129.  The  Control  of  Citrus  Insects.  173. 

136.  Melilotus   indie  a    as   a    Green-Manure 

Crop  for  California.  174. 

144.  Oidium  or  Powdery  Mildew  of  the  Vine.  175. 

151.  Feeding  and  Management  of  Hogs. 

152.  Some  Observations  on  the  Bulk  Hand-  178. 

ling  of  Grain  in  California.  179. 

153.  Announcement  of  the  California  State 

Dairy  Cow  Competition,  1916-18.  182. 

154.  Irrigation  Practice  in  Growing  Small 

Fruit  in  California.  184. 

155.  Bovine  Tuberculosis.  188. 

157.  Control  of  the  Pear  Scab.  190. 

158.  Home  and  Farm  Canning.  193. 
160.  Lettuce  Growing  in  California.  198. 


Potatoes  in  California. 

Small  Fruit  Culture  in  California. 

Fundamentals   of   Sugar   Beet  Culture 

under  California  Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Fertilizing  California  Soils  for  the  1918 

Crop. 
Wheat  Culture. 
The    Construction    of   the   Wood-Hoop 

Silo. 
Farm  Drainage  Methods. 
Progress  Report  on  the  Marketing  and 

Distribution  of  Milk. 
The  Packing  of  Apples  in  California. 
Factors   of    Importance    in    Producing 

Milk  of  Low  Bacterial  Count. 
Extending  the  Area  of  Irrigated  Wheat 

in  California  for  1918. 
A  Flock  of  Sheep  on  the  Farm. 
Lambing  Sheds. 

Agriculture  Clubs  in  California. 
A  Study  of  Farm  Labor  in  California. 
Syrup  fronl*  Sweet  Sorghum. 


CIRCULARS — Continued 


No. 
199. 

201. 
202. 

203. 
205. 
206. 
208. 

209. 
210. 
212. 
214. 

215. 
217. 

218. 

219. 

228. 
230. 

231. 
232. 

233. 
234. 

235. 

236. 


237. 


238. 
239. 


240. 
241. 


Onion  Growing  in  California. 

Helpful  Hints  to  Hog  Raisers. 

County  Organizations  for  Rural  Fire 
Control. 

Peat  as  a  Manure  Substitute. 

Blackleg. 

Jack  Cheese. 

Summary  of  the  Annual  Reports  of  the 
Farm   Advisors  of  California. 

The  Function  of  the  Farm  Bureau. 

Suggestions  to  the  Settler  in  California. 

Salvaging  Rain-Damaged  Prunes. 

Seed  Treatment  for  the  Prevention  of 
Cereal   Smuts. 

Feeding  Dairy  Cows  in  California. 

Methods  for  Marketing  Vegetables  in 
California. 

Advanced  Registry  Testing  of  Dairy 
Cows. 

The  Present   Status  of  Alkali. 

Vineyard   Irrigation  in  Arid  Climates. 

Testing  Milk,  Cream,  and  Skim  Milk 
for  Butterfat. 

The  Home  Vineyard. 

Harvesting  and  Handling  California 
Cherries  for  Eastern  Shipment. 

Artificial  Incubation. 

Winter  Injury  to  Young  Walnut  Trees 
during  1921-22. 

Soil  Analysis  and  Soil  and  Plant  Inter- 
relations. 

The  Common  Hawks  and  Owls  of  Cali- 
fornia from  the  Standpoint  of  the 
Rancher. 

Directions  for  the  Tanning  and  Dress- 
ing of  Furs. 

The  Apricot  in  California. 

Harvesting  and  Handling  Apricots  and 
Plums  for  Eastern   Shipment. 

Harvesting  and  Handling  Pears  for 
Eastern   Shipment. 

Harvesting  and  Handling  Peaches  for 
Eastern   Shipment. 


No. 
243. 

244. 
245. 
247. 
248. 

249. 
250. 

251. 


252. 
253. 
254. 

255. 

256. 
257. 
258. 
259. 
260. 

261. 
262. 
263. 
264. 

265. 
266. 

267. 

268. 

269. 
270. 
271. 


Marmalade  Juice  and  Jelly  Juice  from 
Citrus  Fruits. 

Central  Wire  Bracing  for  Fruit  Trees. 

Vine  Pruning  Systems. 

Colonization  and  Rural  Development. 

Some  Common  Errors  in  Vine  Pruning 
and  Their  Remedies. 

Replacing  Missing  Vines. 

Measurement  of  Irrigation  Water  on 
the  Farm. 

Recommendations  Concerning  the  Com- 
mon Diseases  and  Parasites  of 
Poultry   in    California. 

Supports  for  Vines. 

Vineyard   Plans. 

The  Use  of  Artificial  Light  to  Increase 
Winter  Egg  Production. 

Leguminous  Plants  as  Organic  Fertil- 
izer in  California  Agriculture. 

The  Control  of  Wild  Morning  Glory. 

The  Small- Seeded  Horse  Bean. 

Thinning  Deciduous  Fruits. 

Pear  By-products. 

A  Selected  List  of  References  Relating 
t&  Irrigation  in  California. 

Sewing  Grain  Sacks. 

Cabbage  Growing  in  California. 

Tomato  Production  in  California. 

Preliminary  Essentials  to  Bovine  Tuber- 
culosis  Control. 

Plant  Disease  and  Pest  Control. 

Analyzing  the  Citrus  Orchard  by  Means 
of  Simple  Tree  Records. 

The  Tendency  of  Tractors  to  Rise  in 
Front:  Causes  and  Remedies. 

Inexpensive  Labor-saving  Poultry  Ap- 
pliances. 

An   Orchard  Brush  Burner. 

A  Farm  Septic  Tank. 

Brooding  Chicks  Artificially. 


10m-5,'24 


